Wideband receivers are associated with a large dynamic range. Associated with this dynamic range is frequency splatter. The incoming signal is selected from the wideband range typically by means of a filter. However, an incoming signal will cause frequency splatter extending over the wideband and beyond it and causing energy to be injected into each of the narrow band frequency selective filters. In wideband channelized receivers having contiguous channelized filters a splatter guard function providing an unambiguous indication of an inband signal frequency represents a major element of cost. Prior techniques for analyzing an inband signal involved wide and narrow filters and represented an investment of three filters per channel. An example is shown in U.S. Pat. No. 3,953,802 which uses the combination of wide and narrow band filters for determining when a desired signal is in the narrow band channel.